/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: NodeVector.java,v 1.2.4.1 2005/09/15 08:15:50 suresh_emailid Exp $
 */
package com.sun.org.apache.xml.internal.utils;

import java.io.Serializable;

import com.sun.org.apache.xml.internal.dtm.DTM;

/**
 * A very simple table that stores a list of Nodes.
 * @xsl.usage internal
 */
public class NodeVector implements Serializable, Cloneable {
    static final long serialVersionUID = -713473092200731870L;

    /**
     * Size of blocks to allocate.
     *  @serial
     */
    private int m_blocksize;

    /**
     * Array of nodes this points to.
     *  @serial
     */
    private int m_map[];

    /**
     * Number of nodes in this NodeVector.
     *  @serial
     */
    protected int m_firstFree = 0;

    /**
     * Size of the array this points to.
     *  @serial
     */
    private int m_mapSize; // lazy initialization

    /**
     * Default constructor.
     */
    public NodeVector() {
        m_blocksize = 32;
        m_mapSize = 0;
    }

    /**
     * Construct a NodeVector, using the given block size.
     *
     * @param blocksize Size of blocks to allocate
     */
    public NodeVector(int blocksize) {
        m_blocksize = blocksize;
        m_mapSize = 0;
    }

    /**
     * Get a cloned LocPathIterator.
     *
     * @return A clone of this
     *
     * @throws CloneNotSupportedException
     */
    public Object clone() throws CloneNotSupportedException {

        NodeVector clone = (NodeVector) super.clone();

        if ((null != this.m_map) && (this.m_map == clone.m_map)) {
            clone.m_map = new int[this.m_map.length];

            System.arraycopy(this.m_map, 0, clone.m_map, 0, this.m_map.length);
        }

        return clone;
    }

    /**
     * Get the length of the list.
     *
     * @return Number of nodes in this NodeVector
     */
    public int size() {
        return m_firstFree;
    }

    /**
     * Append a Node onto the vector.
     *
     * @param value Node to add to the vector
     */
    public void addElement(int value) {

        if ((m_firstFree + 1) >= m_mapSize) {
            if (null == m_map) {
                m_map = new int[m_blocksize];
                m_mapSize = m_blocksize;
            } else {
                m_mapSize += m_blocksize;

                int newMap[] = new int[m_mapSize];

                System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

                m_map = newMap;
            }
        }

        m_map[m_firstFree] = value;

        m_firstFree++;
    }

    /**
     * Append a Node onto the vector.
     *
     * @param value Node to add to the vector
     */
    public final void push(int value) {

        int ff = m_firstFree;

        if ((ff + 1) >= m_mapSize) {
            if (null == m_map) {
                m_map = new int[m_blocksize];
                m_mapSize = m_blocksize;
            } else {
                m_mapSize += m_blocksize;

                int newMap[] = new int[m_mapSize];

                System.arraycopy(m_map, 0, newMap, 0, ff + 1);

                m_map = newMap;
            }
        }

        m_map[ff] = value;

        ff++;

        m_firstFree = ff;
    }

    /**
     * Pop a node from the tail of the vector and return the result.
     *
     * @return the node at the tail of the vector
     */
    public final int pop() {

        m_firstFree--;

        int n = m_map[m_firstFree];

        m_map[m_firstFree] = DTM.NULL;

        return n;
    }

    /**
     * Pop a node from the tail of the vector and return the
     * top of the stack after the pop.
     *
     * @return The top of the stack after it's been popped
     */
    public final int popAndTop() {

        m_firstFree--;

        m_map[m_firstFree] = DTM.NULL;

        return (m_firstFree == 0) ? DTM.NULL : m_map[m_firstFree - 1];
    }

    /**
     * Pop a node from the tail of the vector.
     */
    public final void popQuick() {

        m_firstFree--;

        m_map[m_firstFree] = DTM.NULL;
    }

    /**
     * Return the node at the top of the stack without popping the stack.
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     *
     * @return Node at the top of the stack or null if stack is empty.
     */
    public final int peepOrNull() {
        return ((null != m_map) && (m_firstFree > 0)) ? m_map[m_firstFree - 1] : DTM.NULL;
    }

    /**
     * Push a pair of nodes into the stack.
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     *
     * @param v1 First node to add to vector
     * @param v2 Second node to add to vector
     */
    public final void pushPair(int v1, int v2) {

        if (null == m_map) {
            m_map = new int[m_blocksize];
            m_mapSize = m_blocksize;
        } else {
            if ((m_firstFree + 2) >= m_mapSize) {
                m_mapSize += m_blocksize;

                int newMap[] = new int[m_mapSize];

                System.arraycopy(m_map, 0, newMap, 0, m_firstFree);

                m_map = newMap;
            }
        }

        m_map[m_firstFree] = v1;
        m_map[m_firstFree + 1] = v2;
        m_firstFree += 2;
    }

    /**
     * Pop a pair of nodes from the tail of the stack.
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     */
    public final void popPair() {

        m_firstFree -= 2;
        m_map[m_firstFree] = DTM.NULL;
        m_map[m_firstFree + 1] = DTM.NULL;
    }

    /**
     * Set the tail of the stack to the given node.
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     *
     * @param n Node to set at the tail of vector
     */
    public final void setTail(int n) {
        m_map[m_firstFree - 1] = n;
    }

    /**
     * Set the given node one position from the tail.
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     *
     * @param n Node to set
     */
    public final void setTailSub1(int n) {
        m_map[m_firstFree - 2] = n;
    }

    /**
     * Return the node at the tail of the vector without popping
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     *
     * @return Node at the tail of the vector
     */
    public final int peepTail() {
        return m_map[m_firstFree - 1];
    }

    /**
     * Return the node one position from the tail without popping.
     * Special purpose method for TransformerImpl, pushElemTemplateElement.
     * Performance critical.
     *
     * @return Node one away from the tail
     */
    public final int peepTailSub1() {
        return m_map[m_firstFree - 2];
    }

    /**
     * Insert a node in order in the list.
     *
     * @param value Node to insert
     */
    public void insertInOrder(int value) {

        for (int i = 0; i < m_firstFree; i++) {
            if (value < m_map[i]) {
                insertElementAt(value, i);

                return;
            }
        }

        addElement(value);
    }

    /**
     * Inserts the specified node in this vector at the specified index.
     * Each component in this vector with an index greater or equal to
     * the specified index is shifted upward to have an index one greater
     * than the value it had previously.
     *
     * @param value Node to insert
     * @param at Position where to insert
     */
    public void insertElementAt(int value, int at) {

        if (null == m_map) {
            m_map = new int[m_blocksize];
            m_mapSize = m_blocksize;
        } else if ((m_firstFree + 1) >= m_mapSize) {
            m_mapSize += m_blocksize;

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);

            m_map = newMap;
        }

        if (at <= (m_firstFree - 1)) {
            System.arraycopy(m_map, at, m_map, at + 1, m_firstFree - at);
        }

        m_map[at] = value;

        m_firstFree++;
    }

    /**
     * Append the nodes to the list.
     *
     * @param nodes NodeVector to append to this list
     */
    public void appendNodes(NodeVector nodes) {

        int nNodes = nodes.size();

        if (null == m_map) {
            m_mapSize = nNodes + m_blocksize;
            m_map = new int[m_mapSize];
        } else if ((m_firstFree + nNodes) >= m_mapSize) {
            m_mapSize += (nNodes + m_blocksize);

            int newMap[] = new int[m_mapSize];

            System.arraycopy(m_map, 0, newMap, 0, m_firstFree + nNodes);

            m_map = newMap;
        }

        System.arraycopy(nodes.m_map, 0, m_map, m_firstFree, nNodes);

        m_firstFree += nNodes;
    }

    /**
     * Inserts the specified node in this vector at the specified index.
     * Each component in this vector with an index greater or equal to
     * the specified index is shifted upward to have an index one greater
     * than the value it had previously.
     */
    public void removeAllElements() {

        if (null == m_map)
            return;

        for (int i = 0; i < m_firstFree; i++) {
            m_map[i] = DTM.NULL;
        }

        m_firstFree = 0;
    }

    /**
     * Set the length to zero, but don't clear the array.
     */
    public void RemoveAllNoClear() {

        if (null == m_map)
            return;

        m_firstFree = 0;
    }

    /**
     * Removes the first occurrence of the argument from this vector.
     * If the object is found in this vector, each component in the vector
     * with an index greater or equal to the object's index is shifted
     * downward to have an index one smaller than the value it had
     * previously.
     *
     * @param s Node to remove from the list
     *
     * @return True if the node was successfully removed
     */
    public boolean removeElement(int s) {

        if (null == m_map)
            return false;

        for (int i = 0; i < m_firstFree; i++) {
            int node = m_map[i];

            if (node == s) {
                if (i > m_firstFree)
                    System.arraycopy(m_map, i + 1, m_map, i - 1, m_firstFree - i);
                else
                    m_map[i] = DTM.NULL;

                m_firstFree--;

                return true;
            }
        }

        return false;
    }

    /**
     * Deletes the component at the specified index. Each component in
     * this vector with an index greater or equal to the specified
     * index is shifted downward to have an index one smaller than
     * the value it had previously.
     *
     * @param i Index of node to remove
     */
    public void removeElementAt(int i) {

        if (null == m_map)
            return;

        if (i > m_firstFree)
            System.arraycopy(m_map, i + 1, m_map, i - 1, m_firstFree - i);
        else
            m_map[i] = DTM.NULL;
    }

    /**
     * Sets the component at the specified index of this vector to be the
     * specified object. The previous component at that position is discarded.
     *
     * The index must be a value greater than or equal to 0 and less
     * than the current size of the vector.
     *
     * @param node Node to set
     * @param index Index of where to set the node
     */
    public void setElementAt(int node, int index) {

        if (null == m_map) {
            m_map = new int[m_blocksize];
            m_mapSize = m_blocksize;
        }

        if (index == -1)
            addElement(node);

        m_map[index] = node;
    }

    /**
     * Get the nth element.
     *
     * @param i Index of node to get
     *
     * @return Node at specified index
     */
    public int elementAt(int i) {

        if (null == m_map)
            return DTM.NULL;

        return m_map[i];
    }

    /**
     * Tell if the table contains the given node.
     *
     * @param s Node to look for
     *
     * @return True if the given node was found.
     */
    public boolean contains(int s) {

        if (null == m_map)
            return false;

        for (int i = 0; i < m_firstFree; i++) {
            int node = m_map[i];

            if (node == s)
                return true;
        }

        return false;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem Node to look for
     * @param index Index of where to start the search
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public int indexOf(int elem, int index) {

        if (null == m_map)
            return -1;

        for (int i = index; i < m_firstFree; i++) {
            int node = m_map[i];

            if (node == elem)
                return i;
        }

        return -1;
    }

    /**
     * Searches for the first occurence of the given argument,
     * beginning the search at index, and testing for equality
     * using the equals method.
     *
     * @param elem Node to look for
     * @return the index of the first occurrence of the object
     * argument in this vector at position index or later in the
     * vector; returns -1 if the object is not found.
     */
    public int indexOf(int elem) {

        if (null == m_map)
            return -1;

        for (int i = 0; i < m_firstFree; i++) {
            int node = m_map[i];

            if (node == elem)
                return i;
        }

        return -1;
    }

    /**
     * Sort an array using a quicksort algorithm.
     *
     * @param a The array to be sorted.
     * @param lo0  The low index.
     * @param hi0  The high index.
     *
     * @throws Exception
     */
    public void sort(int a[], int lo0, int hi0) throws Exception {

        int lo = lo0;
        int hi = hi0;

        // pause(lo, hi);
        if (lo >= hi) {
            return;
        } else if (lo == hi - 1) {

            /*
             *  sort a two element list by swapping if necessary
             */
            if (a[lo] > a[hi]) {
                int T = a[lo];

                a[lo] = a[hi];
                a[hi] = T;
            }

            return;
        }

        /*
         *  Pick a pivot and move it out of the way
         */
        int pivot = a[(lo + hi) / 2];

        a[(lo + hi) / 2] = a[hi];
        a[hi] = pivot;

        while (lo < hi) {

            /*
             *  Search forward from a[lo] until an element is found that
             *  is greater than the pivot or lo >= hi
             */
            while (a[lo] <= pivot && lo < hi) {
                lo++;
            }

            /*
             *  Search backward from a[hi] until element is found that
             *  is less than the pivot, or lo >= hi
             */
            while (pivot <= a[hi] && lo < hi) {
                hi--;
            }

            /*
             *  Swap elements a[lo] and a[hi]
             */
            if (lo < hi) {
                int T = a[lo];

                a[lo] = a[hi];
                a[hi] = T;

                // pause();
            }

            // if (stopRequested) {
            //    return;
            // }
        }

        /*
         *  Put the median in the "center" of the list
         */
        a[hi0] = a[hi];
        a[hi] = pivot;

        /*
         *  Recursive calls, elements a[lo0] to a[lo-1] are less than or
         *  equal to pivot, elements a[hi+1] to a[hi0] are greater than
         *  pivot.
         */
        sort(a, lo0, lo - 1);
        sort(a, hi + 1, hi0);
    }

    /**
     * Sort an array using a quicksort algorithm.
     *
     * @throws Exception
     */
    public void sort() throws Exception {
        sort(m_map, 0, m_firstFree - 1);
    }
}
